<template>
    <div class="s-canvas" @click="drawPic" title="点击刷新">
        <canvas id="s-canvas" :width="props.contentWidth" :height="props.contentHeight"></canvas>
    </div>
</template>

<script setup>
  import { onMounted, watch ,defineProps,defineEmits,nextTick} from 'vue';

  const props = defineProps({
    code: {},   //验证码
    type: { //blend混合，number数字，letter字段
      type: String,
      default: 'number'
    },
    size: { //验证值长度
      type: Number,
      default: 4
    },
    identifyCode: {
      type: String,
      default: 'abzc'
    },
    fontSizeMin: {
      type: Number,
      default: 35
    },
    fontSizeMax: {
      type: Number,
      default: 35
    },
    backgroundColorMin: {
      type: Number,
      default: 180
    },
    backgroundColorMax: {
      type: Number,
      default: 240
    },
    colorMin: {
      type: Number,
      default: 50
    },
    colorMax: {
      type: Number,
      default: 160
    },
    lineColorMin: {
      type: Number,
      default: 100
    },
    lineColorMax: {
      type: Number,
      default: 200
    },
    dotColorMin: {
      type: Number,
      default: 0
    },
    dotColorMax: {
      type: Number,
      default: 255
    },
    contentWidth: {
      type: Number,
      default: 120
    },
    contentHeight: {
      type: Number,
      default: 40
    }
  }),
    emit = defineEmits(['update:code'])
  const numArr = ['0','1','2','3','4','5','6','7','8','9'],
    letterArr = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'];

  let curCode = '';

  // 生成一个随机数
  const randomNum = (min, max) => {
    return Math.floor(Math.random() * (max - min) + min)
  }

  // 生成一个随机的颜色
  const randomColor = (min, max) => {
    let r = randomNum(min, max)
    let g = randomNum(min, max)
    let b = randomNum(min, max)
    return 'rgb(' + r + ',' + g + ',' + b + ')'
  }

  // 绘制干扰线
  const drawLine = (ctx) => {
    for (let i = 0; i < 3; i++) {
      ctx.strokeStyle = randomColor(props.lineColorMin, props.lineColorMax)
      ctx.beginPath()
      ctx.moveTo(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight))
      ctx.lineTo(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight))
      ctx.stroke()
    }
  }

  const drawText = (ctx,txt, i) => {
    curCode += txt;
    ctx.fillStyle = randomColor(props.colorMin, props.colorMax)
    ctx.font = randomNum(props.fontSizeMin, props.fontSizeMax) + 'px SimHei'
    let x = (i + 1) * (props.contentWidth / (props.identifyCode.length + 1))
    let y = randomNum(props.fontSizeMax, props.contentHeight - 5)
    var deg = randomNum(-10, 10)
    // 修改坐标原点和旋转角度
    ctx.translate(x, y)
    ctx.rotate(deg * Math.PI / 100)
    ctx.fillText(txt, 0, 0)
    // 恢复坐标原点和旋转角度
    ctx.rotate(-deg * Math.PI / 100)
    ctx.translate(-x, -y)
  }

  const drawDot = (ctx) => {
    // 绘制干扰点
    for (let i = 0; i < 30; i++) {
      ctx.fillStyle = randomColor(0, 255)
      ctx.beginPath()
      ctx.arc(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight), 1, 0, 2 * Math.PI)
      ctx.fill()
    }
  }

  const drawPic = () => {
    let canvas = document.getElementById('s-canvas')
    let ctx = canvas.getContext('2d')
    ctx.textBaseline = 'bottom'
    // 绘制背景
    ctx.fillStyle = randomColor(props.backgroundColorMin, props.backgroundColorMax)
    ctx.fillRect(0, 0, props.contentWidth, props.contentHeight)

    //文字组合
    let txtArr = [];
    if (props.type === 'blend') txtArr = [...numArr,...letterArr];
    else if (props.type === 'letter') txtArr = letterArr;
    else txtArr = numArr;

    curCode = '';
    // 绘制文字
    for (let i = 0; i < props.size; i++) {
      drawText(ctx,txtArr[randomNum(0, txtArr.length)], i)
    }
    drawLine(ctx)
    drawDot(ctx)
    console.log(curCode);
    emit('update:code',curCode)
  }

  const validate = (code) =>{
    return code.toLowerCase() == curCode.toLowerCase()
  }

  watch(() => props.identifyCode, (newValue, oldValue) => {
    drawPic()
  })

  onMounted(() => {
    nextTick(() => drawPic());
  })

    defineExpose({refresh: drawPic,validate})
</script>
<style scoped lang='less'>
    .s-canvas {
        cursor: pointer;
    }
</style>
